Symptoms of a medical or behavioral problem may be necessary for parents to seek medical care for their children, but children's health and mental health need is not sufficient to predict inadequate or excessive care-seeking by parents. In addition to need variables, pediatric medical care-seeking is thought to be influenced by predisposing and enabling factors of both parent and child. Descriptive retrospective studies have identified correlates of both high and low pediatric care-seeking, but a dependence on retrospective databases has limited evaluation of a range of possible determinants of pediatric care-seeking. Results of several large scale surveys suggest that a combination of predisposing, enabling, and need variables, collected prospectively, may be more powerful predictors of children's medical care use. We hypothesize that family functioning, stressful life events, and parents' learned ways of responding to symptoms and distress are important determinants of medical care seeking for children. We propose to study determinants of pediatric medical care utilization. Subjects will be members of a large, suburban health maintenance organization recruited from low, medium, and high users of medical care services during a 2 year period, as well as children who do not receive care. Prospective measures of children's health and behavioral status and of their parents' mental health status, stressful life events, and family functioning will be evaluated for relationships with medical care-seeking. Medical care-seeking by both parents and children for 2-year retrospective and prospective periods will be analyzed to determine the strongest predictors of low and high pediatric medical care use, with emphases on identifying modifiable factors which control care-seeking. This study, which prospectively evaluates relevant predisposing and need variables while controlling for enabling factors, will contribute to the development of a person-based model which advances understanding of the influence of psychosocial factors on pediatric medical care-seeking. The results will provide direction for the development of expanded health, behavioral, and psychological services into pediatric health care systems and the evaluation of behavioral, mental, and physical health outcomes associated with targeted services which meet the needs of parents and children.